U.S. patent number 4,018,497 [Application Number 05/634,418] was granted by the patent office on 1977-04-19 for joint for electrical conductors.
This patent grant is currently assigned to Midland-Ross Corporation. Invention is credited to William J. Bulanchuk.
United States Patent |
4,018,497 |
Bulanchuk |
April 19, 1977 |
Joint for electrical conductors
Abstract
A joint for electrical conductors includes a connecting member
having a longitudinal groove therein for receiving joining portions
on a pair of electrical conductors. Biasing means carried by the
conductors act against the groove bottom for biasing joining
surfaces on the conductors into firm engagement with joining groove
surfaces. The joint accommodates longitudinal thermal expansion and
contraction of busbars or the like.
Inventors: |
Bulanchuk; William J. (Pelham,
NY) |
Assignee: |
Midland-Ross Corporation
(Cleveland, OH)
|
Family
ID: |
24543702 |
Appl.
No.: |
05/634,418 |
Filed: |
November 24, 1975 |
Current U.S.
Class: |
439/115;
191/44.1; 439/819; 174/94S; 403/393 |
Current CPC
Class: |
H02G
5/04 (20130101); H02G 5/002 (20130101); Y10T
403/7152 (20150115) |
Current International
Class: |
H02G
5/04 (20060101); H02G 5/00 (20060101); H01R
011/22 () |
Field of
Search: |
;339/22R,22B,47,244R,255R,255L,256R,256S,273S ;174/94S,99E
;191/44.1 ;403/341,393 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Bicks; Mark S.
Attorney, Agent or Firm: Switzer; H. Duane
Claims
I claim:
1. A joint comprising a pair of elongated electrical conductors
having end portions which are connected, said end portions having
longitudinal axes, main body portions and joining portions, said
joining portions having joining portion surfaces facing generally
toward said main body portions in spaced relationship thereto, a
connecting member having a longitudinal groove therein, said groove
having a longitudinal groove opening along the length of said
connecting member and opposite end groove openings at the opposite
ends of said connecting member, said groove having a groove bottom
spaced inwardly of said connecting member from said longitudinal
groove opening, said groove having joining groove surfaces facing
generally toward said groove bottom, said end portions of said
conductors having said joining portions extending into said groove
through said end groove openings with said longitudinal axes
aligned, said main body portions of said end portions being located
outside said groove adjacent said longitudinal groove opening, and
independent yieldable biasing means mounted on and carried by each
said joining portion on each said end portion independently of said
connecting member for biasing against said groove bottom and urging
said joining portion surfaces into engagement with said joining
groove surfaces.
2. The joint of claim 1 wherein said biasing means comprises a
metal spring member on each said end portion, said spring member
having a connecting portion for connection with said joining
portion, and a bowed spring extending from said connecting portion
toward the free end of each said end portion.
3. The joint of claim 2 wherein said connecting portion includes a
first portion receiving said joining portions in engagement with
said joining surfaces and a second portion extending rearwardly
from said first portion and having a downwardly extending bent
portion, said joining portion having a slot therein extending
generally perpendicular to said axes, and said downwardly extending
bent portion being received in said slot.
4. The joint of claim 1 including a holder of dielectric material
receiving said connecting member.
5. The joint of claim 1 wherein said main body portion has a flat
outer surface opposite from said joining portion and opposite side
edges, said end portions of said conductors having terminal ends
extending diagonally of said longitudinal axes, said terminal end
on each said conductor intersecting one of said side edges at an
included obtuse angle to define an obtuse corner and intersecting
the other of said side edges at an included acute angle to define
an acute corner, and said conductors being positioned with said
obtuse corner on one facing said acute corner on the other.
6. The joint of claim 5 wherein said acute corner is cut off along
a line extending generally perpendicular to said axes, said line
having a length substantially less than the distance from said
other side edge to said axes.
7. The joint of claim 6 wherein said terminal ends on said
conductors are longitudinally spaced-apart from one another a small
distance.
8. The joint of claim 1 wherein said conductors have terminal ends
longitudinally spaced-apart from one another a small distance.
9. An elongated electrical conductor having a longitudinal axis and
an end portion including a terminal end, said conductor including a
main body portion having a generally flat outer surface and an
integral joining portion extending from said main body portion
opposite from said flat outer surface, said joining portion having
joining surfaces facing generally toward said main body portion in
outwardly-spaced relationship thereto, joining means attached to
said joining portion at said end portion for joining said end
portion to a connector, said joining means comprising a one-piece
joining member including an attaching portion receiving said
joining portion and an integral bowed spring portion extending
upwardly and then downwardly in a direction from said attaching
portion toward said terminal end, and said attaching portion and
said joining portion being fixed against longitudinal movement
relative to one another.
10. The conductor of claim 9 wherein said terminal end extends
diagonally of said axis and said main body portion has opposite
side edges, said terminal end intersecting one of said side edges
at an included obtuse angle to define an obtuse corner, said
terminal end intersecting the other of said side edges at an
included acute angle to define an acute corner, said acute corner
being cut along a line extending generally perpendicular to said
axis, and said line having a length substantially less than the
distance between said other side edge and said axis.
11. The conductor of claim 9 wherein said bowed spring portion has
a free end portion engaging said joining portion and said bowed
spring portion is stressed, said free end portion being freely
slidably movable longitudinally of said joining portion.
12. The conductor of claim 11 wherein said free end portion is
flattened to facilitate sliding thereof on said joining portion
when said bowed spring portion is further stressed by deforming
same toward said joining portion.
13. An elongated electrical conductor having a longitudinal axis
and an end portion including a terminal end, said conductor
including a main body portion having a generally flat outer surface
and an integral joining portion extending from said main body
portion opposite from said flat outer surface, said joining portion
having joining surfaces facing generally toward said main body
portion in outwardly-spaced relationship thereto and having a
transverse slot therein, joining means attached to said joining
portion at said end portion for joining said end portion to a
connector, said joining means including an attaching portion
receiving said joining portion, said attaching portion including a
rearwardly extending tang having a downwardly bent portion received
in said slot, and said joining means including a bowed spring
portion extending upwardly and then downwardly in a direction from
said attaching portion toward said terminal end.
Description
BACKGROUND OF THE INVENTION
This application relates to the art of electrical connections and,
more particularly, to joints between elongated rigid conductors.
The invention is particularly applicable to joints between
electrical busbars used in trolley busway systems and will be
particularly described with reference thereto. However, it will be
recognized that the improved electrical joint of the present
application can be used with conductors other than busbars in
trolley busway systems.
Trolley busway systems commonly include a housing surrounding and
carrying a plurality of busbars. A trolley rides along a track in
the housing and has brushes engaging the busbars. Housing sections
must be joined together for assembling a complete trolley busway
system and the busbars in each housing section must also be
connected together. Busbar connectors requiring the use of screws
and the like make joining thereof very time consuming. The joints
must also be relatively smooth so the brushes on the trolley will
not come out of engagement with the busbars when the brushes cross
a joint. With rigid joints, longitudinal thermal expansion and
contraction of the busbars may cause same to buckle or otherwise
fail.
It would be desirable to have a busbar joint which could be made
without requiring the use of screws or the like, while providing a
very secure joint which accommodates longitudinal thermal expansion
and contraction of busbars and maintains excellent current carrying
ability, and provides a smooth transition from one busbar to
another.
SUMMARY OF THE INVENTION
A joint for elongated rigid electrical conductors of the type
including a main body portion having a generally flat outer surface
and a joining portion extending from the main body portion opposite
from the flat outer surface for reception in a connecting member to
form the joint. The joining portion has joining surfaces facing
generally toward the main body portion in outwardly-spaced
relationship thereto.
A connecting member has a longitudinal groove therein including a
longitudinal groove opening and opposite end groove openings. The
groove has a bottom spaced from the longitudinal groove opening and
includes groove joining surfaces facing generally toward the groove
bottom in outwardly-spaced relationship thereto.
A pair of conductors have the joining portions on their end
portions received through the open groove ends, with the main body
portions of the end portions located outside of the groove adjacent
the longitudinal groove opening. Yieldable biasing means carried by
each conductor end portion biases against the groove bottom for
urging the joining surfaces on the joining portions and groove into
firm engagement with one another.
In one arrangement, the yieldable biasing means comprises joining
means having an attaching portion receiving the joining portion on
each conductor for attaching the joining means thereto. A bowed
spring portion extends upwardly and then downwardly from the
attaching portion in a direction from the attaching portion toward
the terminal end of each conductor. An integral tang on the
attaching portion extends therefrom in a direction opposite to the
bowed spring, and the tang has a downwardly bent portion received
in a transverse slot in the joining portion for preventing
longitudinal movement of the joining means relative to the
conductor. line to
The bowed spring is preferably stressed so that its outer end
engages the joining portion before the joining portions are
positioned in the groove. The bowed spring is further stressed by
deformation thereof toward the joining portion by engagement with
the groove bottom. The outer end of the bowed spring is preferably
flattened for facilitating sliding movement thereof relative to the
joining portion when the bowed spring is deformed toward the
joining portion.
In accordance with another aspect of the invention, the terminal
end of each conductor extends diagonally of the conductor
longitudinal axis and the flat outer surface or main body portion
of the conductor has opposite side edges. The diagonal terminal end
intersects one side edge at an included obtuse angle to define an
obtuse corner, while intersecting the other side edge at an
included acute angle to define an acute corner. The acute corner is
cut off along a line extending generally perpendicular to the
conductor longitudinal axis, and the lines has a length which is
less than the distance from the other side edge of the conductor
longitudinal axis. The conductors are positioned in the connecting
member with the obtuse corner on one terminal end facing the acute
corner on the other terminal end.
The busbars are positioned with their terminal ends spaced-apart
slightly when the joint is first assembled so the connecting member
and terminal ends can move longitudinally relative to one another
for accommodating longitudinal thermal expansion and contraction of
the busbars.
It is a principal object of the present invention to provide an
improved joint between electrical conductors.
It is also an object of the present invention to provide an
improved joint having a smooth transition so that brushes of a
trolley sliding along the conductor will not be separated from the
conductors when they pass over the joint.
It is an additional object of the invention to provide an improved
electrical joint which is easily made without requiring the use of
screws or the like.
It is another object of the invention to provide an electrical
joint which accommodates thermal expansion and contraction of
conductors while maintaining full current carrying capability.
It is a further object of the invention to provide an improved
electrical joint which is very secure and provides good
conductivity from one conductor to another past the joint.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective illustration of the improved joint of the
present application;
FIG. 2 is a top elevational view of a joint between a pair of
electrical conductors;
FIG. 3 is a side elevational view of a joint between a pair of
electrical conductors, and with portions cut away for clarity of
illustration, and with one conductor being shown positioned for
movement into a connecting member;
FIG. 4 is a cross-sectional elevational view taken generally on
line 4--4 of FIG. 3;
FIG. 5 is a bottom elevational view looking generally in the
direction of arrows 5--5 of FIG. 4;
FIG. 6 is a side elevational view of a joining means which includes
yieldable biasing means;
FIG. 7 is a top plan view looking generally in the direction of
arrows 7--7 of FIG. 6; and
FIG. 8 is a cross-sectional elevational view taken generally on
line 8--8 of FIG. 6.
DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to the drawing, wherein the showings are for purposes
of illustrating a preferred embodiment of the invention only and
not for purposes of limiting same, FIG. 1 shows a pair of elongated
rigid electrical conductors each having a main body portion A and a
connecting portion B. Main body portion A has a substantially flat
outer surface 12 and opposite longitudinal side edges 14. Integral
joining portion B is centrally located on main body portion A and
extends outwardly therefrom opposite from flat outer surface
12.
In the arrangement shown, joining portion B is generally V-shaped
in cross section. Joining portion B is integrally connected with
body portion A by a relatively narrow portion and then diverges
outwardly. Joining portion B has opposite outer joining surfaces 18
which face generally toward main body portion A in spaced
relationship thereto.
Joining means C which includes yieldable biasing means is attached
to the joining portion on the terminal end portion of each
conductor. Joining means C includes an attaching portion generally
indicated at 22 having a top flat portion with downwardly and
inwardly extending legs 24 as shown in FIG. 8. The top flat portion
of attaching portion 22 cooperates with legs 24 to define a groove
having generally the same cross-sectional size and shape as joining
portion B. A bowed spring 26 is smoothly bent upwardly and then
downwardly from attaching portion 22 in a direction from attaching
portion 22 toward the terminal end of a conductor. The free end of
bowed spring 26 is flattened as at 28 and engages joining portion
B. When joining means C is secured to a conductor, bowed spring 26
is stressed somewhat so that flat terminal end portion 28 is firmly
engaging joining portion B. Flattened end portion 28 facilitates
sliding movement of the end portion of bowed spring 26 on joining
portion B when bowed spring 26 is stressed by deforming it toward
joining portion B.
A tang 30 extends rearwardly from attaching portion 22 in a
direction opposite from bowed spring 26 and has a widened
downwardly bent reversely curved portion 32 received in a
transverse slot 34 in joining portion B for locking joining means C
against longitudinal movement relative to the conductor.
Terminal end 38 of each conductor extends diagonally of conductor
longitudinal axes 40. Each terminal end 38 may extend at an angle
of approximately 45.degree. with respect to longitudinal axes 40.
Each terminal end 38 intersects one side edge 14 at an included
obtuse angle to define an obtuse corner 42 and intersects the other
side edge 14 at an included acute angle to define an acute corner
44. The acute corners are cut off along a line 46 extending
generally perpendicular to axes 40, and have a length substantially
less than the distance from one side edge 14 to longitudinal axes
40.
An elongated metal connecting member D has a longitudinal groove 50
therein which is narrower where it opens outwardly longitudinally
of connecting member D than interiorly thereof. Groove 50 includes
a groove bottom 52 spaced inwardly of connecting member D from the
longitudinal groove opening therein, and opposite groove sidewalls
54 which define groove joining surfaces facing generally toward
groove bottom 52. Groove 50 has opposite groove end openings at the
opposite ends of connecting member D. The cross-sectional shape of
groove 50 is generally similar to the cross-sectional shape of
joining portion B, and of somewhat larger cross-sectional size.
Groove joining surfaces 54 slope at generally the same angle as
joining surfaces 18 of joining portion B and the longitudinal
groove opening is narrower than a major portion of the height of
joining portion B. A cover member E of synthetic plastic material
having a dielectric constant substantially greater than unity
covers the bottom and sides of connecting member D for insulating
adjacent joints from one another. Without cover member E, the air
gap between adjacent connecting members D would be too small in
some instances to provide sufficient electrical insulation. The
opposite ends of cover member E have inwardly sloping walls 60
which slope toward the opposite groove end openings at the opposite
ends of connecting member D for aiding insertion of joining
portions on the connectors into the ends of groove 50.
As best shown in FIG. 3, an end portion of a conductor is moved
toward connecting member D with the terminal end of joining portion
B aligned with an open groove end of groove 50. Axial force is
applied for moving the conductor and connecting member
longitudinally toward one another so that joining portion B slides
into groove 50 with joining surfaces 18 of joining portion B
engaging groove joining surfaces 54. In the normal position of
bowed spring 26, it projects outwardly from joining portion B a
distance substantially greater than the distance from joining
portion B to groove bottom 52. Therefore, when an end portion of a
conductor is longitudinally telescoped within groove 50, bowed
spring 26 is further stressed by being bent toward joining portion
B. This renders bowed spring 26 a yieldable biasing means for
biasing joining portion B away from groove bottom 52 for firmly
engaging joining surfaces 18 and 54. The frictional engagement
between spring 26 and groove bottom 52, and between joining
surfaces 18 and 54, makes a very secure joint which is not easily
separated and provides good conductive paths from one conductor to
the other across the joint.
The obtuse corner 42 on one conductor faces toward the acute corner
44 on the other conductor as shown in FIG. 5. The diagonal joint
formed between diagonal terminal ends 38 insures a smooth joint so
that brushes on a trolley will cross the joint from one conductor
to another without bouncing out of engagement with the conductors.
Conductors of the type described are sometimes twisted slightly
when they are positioned within the connecting member. In the event
there is some relative twist between the conductors, the sharp
peaks at acute corners 44 would normally cause a rather large drop
across the joint so the brushes on the trolley might come out of
engagement with the conductors. Cutting off the peaks of the acute
corners as shown in FIG. 5 substantially eliminates any step even
if the conductors are slightly twisted relative to one another.
The terminal end portions of conductors A are assembled within
connecting member D with terminal ends 38 thereof longitudinally
spaced-apart from one another a relatively small distance. This
spacing will depend upon the size of the conductors and the
temperature variations expected. In one arrangement, this spacing
has been approximately 3/32 inch. Although the joint is very secure
and strongly held together by frictional engagement between the
parts, longitudinal relative sliding movement between the
connecting member and conductors can take place for accommodating
thermal expansion and contraction when terminal ends 38 are
longitudinally spaced from one another a small distance and legs 24
on joining means C are spaced outwardly slightly from the ends of
metal connecting member D. The temperature of the conductors varies
with ambient temperature and with variations in current flow. The
gap or space between conductor terminal ends, and the frictional
assembly of the joint, freely allows expansion and contraction
while maintaining full current carrying capability across the
joint. The normal temperature operating range is such that the gap
between the conductor terminal ends will not become sufficiently
large to prevent a smooth transition of the trolley contacts past
the joint. The gap between the conductor terminal ends is
sufficiently small that the end portions defined by lines 46 of the
cut-off peaks always overlap one another a substantial distance on
opposite sides of axis 40.
Joining means C is applied to a connecting portion B by resiliently
bending tang 30 upwardly and inserting a joining portion B
longitudinally between legs 24 of FIG. 8. Joining means C is then
slid longitudinally along joining portion B until downwardly bent
reversely curved portion 32 on tang 30 snaps into transverse groove
34. The distance along the center longitudinal axis of a conductor
from a terminal end 38 to the edges of attaching portion 22 is not
less than the distance from one terminal end of connecting member D
to the midpoint thereof along groove 50. This insures that terminal
ends 38 of two conductors will firmly abut one another as shown in
FIG. 5 before the forward edges of attaching portions 22 abut the
terminal ends of connecting member D adjacent the groove end
openings therein.
Although the invention has been shown and described with respect to
a preferred embodiment, it is obvious that equivalent alterations
and modifications will occur to others skilled in the art upon the
reading and understanding of this specification. The present
invention includes all such equivalent alterations and
modifications, and is limited only by the scope of the claims.
* * * * *